PLANT GROUPS Division Charophyta Class Charophyceae Order Charales Family Charaece Genus Chara

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PLANT GROUPS

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1) The plant body consists of an erect axis differentiated into nodes & internodes with laterals growth at the nodes. 2) The reproductive organs are complex & are surrounded by a layer of sterile tissue 3) The motile male gamete, Antherozoid is an elongated biflagellate spiral structure.

Division Charophyta Class Charophyceae Order Charales Family Charaece Genus Chara

Chara is submerged aquatic alga, consisting of an erect branched axis attached to the substratum by multicellular rhizoid, the plants grow to a height of (5-130 cm) & resembles in appearance to a miniature horse tail. The plant body is differentiated into nodes & internodes form each node a whorl of short laterals maybe limited or unlimited.

1 PLANT GROUPS charophyta

Chara

Life Cycle

Reproduction: Only two kinds of reproduction the vegetative & the sexual are found in Chara.

Vegetative Reproduction

1. Amylum stars: Each amylum star is an aggregation of cells, looking like a star. 2. Bulbils: These are small rounded tuber like structure which is developed on the Rhizoids.

2 PLANT GROUPS charophyta

Sexual Reproduction is advanced Oogamy

Amylum star

Bulbils

Chara (1n)

Globule (1n) Nucule (1n)

Antheridium (1n) Oogonium (1n) Protonema (1n)

Antherozoid Ovum

Fertilization

Meiosis

Oospore

Graphic representation life cycle of Chara

3 PLANT GROUPS charophyta

Division Charophyta

Class Charophyceae Order Charales Family Charaece

Genus Nitella

Nitella this genus resembles Chara it also subaquatic but unlike Chara it grows in much deeper water. Plant body in Nitella more branched & does not have calcareous deposition. The mode of sexual reproduction organs in Chara the Nucule directed upwards & Globule downwards but in Nitella the Globule being directed upwards (Terminal) & the Nucule downwards (Lateral).

The Nucule is relatively less elongated than Chara & has 10-celled coronal arranged in two tiers which are small while in Chara 5-celled coronal & large.

4 PLANT GROUPS charophyta

Chara Nitella

Chara

5 PLANT GROUPS charophyta

6 PLANT GROUPS charophyta